This invention relates generally to gonadotropin-releasing hormone (GnRH) receptor antagonists, and to methods of treating disorders by administration of such antagonists to a warm-blooded animal in need thereof.
Gonadotropin-releasing hormone (GnRH), also known as luteinizing hormone- releasing hormone (LHRH), is a decapeptide (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) that plays an important role in human reproduction. GnRH is released from the hypothalamus and acts on the pituitary gland to stimulate the biosynthesis and release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH released from the pituitary gland is responsible for the regulation of gonadal steroid production in both males and females, while FSH regulates spermatogenesis in males and follicular development in females.
Due to its biological importance, synthetic antagonists and agonists to GnRH have been the focus of considerable attention, particularly in the context of prostate cancer, breast cancer, endometriosis, uterine leiomyoma, and precocious puberty. For example, peptidic GnRH agonists, such as leuprorelin (pGlu-His-Trp-Ser-Tyr-D-Leu-Leu-Arg-Pro-NHEt), have been used to treat such conditions. Such agonists appear to function by binding to the GnRH receptor in the pituitary gonadotropins, thereby inducing the synthesis and release of gonadotropins. Chronic administration of GnRH agonists depletes gonadotropins and subsequently down-regulates the receptor, resulting in suppression of steroidal hormones after some period of time (e.g., on the order of 2-3 weeks following initiation of chronic administration).
In contrast, GnRH antagonists are believed to suppress gonadotropins from the onset, and thus have received the most attention over the past two decades. To date, some of the primary obstacles to the clinical use of such antagonists have been their relatively low bioavailability and adverse side effects caused by histamine release. However, several peptidic antagonists with low histamine release properties have been reported, although they still must be delivered via sustained delivery routes (such as subcutaneous injection or intranasal spray) due to limited bioavailability.
In view of the limitations associated with peptidic GnRH antagonists, a number of nonpeptidic compounds have been proposed. For example, Cho et al. (J. Med. Chem. 41:4190-4195, 1998) discloses thieno[2,3-b]pyridin-4-ones for use as GnRH receptor antagonists; U.S. Pat. Nos. 5,780,437 and 5,849,764 teach substituted indoles as GnRH receptor antagonists (as do published PCTs WO 97/21704, 98/55479, 98/55470, 98/55116, 98/55119, 97/21707, 97/21703 and 97/21435); published PCT WO 96/38438 discloses tricyclic diazepines as GnRH receptor antagonists; published PCTs WO97/14682, 97/14697 and 99/09033 disclose quinoline and thienopyridine derivatives as GnRH antagonists; published PCTs WO 97/44037, 97/44041, 97/44321 and 97/44339 teach substituted quinolin-2-ones as GnRH receptor antagonists; and published PCT WO 99/33831 discloses certain phenyl-substituted fused nitrogen-containing bicyclic compounds as GnRH receptor antagonists.
While significant strides have been made in this field, there remains a need in the art for effective small molecule GnRH receptor antagonists. There is also a need for pharmaceutical compositions containing such GnRH receptor antagonists, as well as methods relating to the use thereof to treat, for example, sex-hormone related conditions. The present invention fulfills these needs, and provides other related advantages.
In brief, this invention is generally directed to gonadotropin-releasing hormone (GnRH) receptor antagonists, as well as to methods for their preparation and use, and to pharmaceutical compositions containing the same. More specifically, the GnRH receptor antagonists of this invention are compounds having the following general structure (I): 
including stereoisomers, prodrugs and pharmaceutically acceptable salts thereof, wherein A, Q, R1, R2, R3a, R3b, R4, R5, R6, and n are as defined below.
The GnRH receptor antagonists of this invention have utility over a wide range of therapeutic applications, and may be used to treat a variety of sex-hormone related conditions in both men and women, as well as a mammal in general (also referred to herein as a xe2x80x9csubjectxe2x80x9d). For example, such conditions include endometriosis, uterine fibroids, polycystic ovarian disease, hirsutism, precocious puberty, gonadal steroid-dependent neoplasia such as cancers of the prostate, breast and ovary, gonadotrophe pituitary adenomas, sleep apnea, irritable bowel syndrome, premenstrual syndrome, benign prostatic hypertrophy, contraception and infertility (e.g., assisted reproductive therapy such as in vitro fertilization). The compounds of this invention are also useful as an adjunct to treatment of growth hormone deficiency and short stature, and for the treatment of systemic lupus erythematosis. The compounds are also useful in combination with androgens, estrogens, progesterones, and antiestrogens and antiprogestogens for the treatment of endometriosis, fibroids, and in contraception, as well as in combination with an angiotensin-converting enzyme inhibitor, an angiotensin II-receptor antagonist, or a renin inhibitor for the treatment of uterine fibroids. In addition, the compounds may be used in combination with bisphosphonates and other agents for the treatment and/or prevention of disturbances of calcium, phosphate and bone metabolism, and in combination with estrogens, progesterones and/or androgens for the prevention or treatment of bone loss or hypogonadal symptoms such as hot flashes during therapy with a GnRH antagonist.
The methods of this invention include administering an effective amount of a GnRH receptor antagonist, preferably in the form of a pharmaceutical composition, to a mammal in need thereof. Thus, in still a further embodiment, pharmaceutical compositions are disclosed containing one or more GnRH receptor antagonists of this invention in combination with a pharmaceutically acceptable carrier and/or diluent.
These and other aspects of the invention will be apparent upon reference to the following detailed description. To this end, various references are set forth herein which describe in more detail certain background information, procedures, compounds and/or compositions, and are each hereby incorporated by reference in their entirety.
As mentioned above, the present invention is directed generally to compounds useful as gonadotropin-releasing hormone (GnRH) receptor antagonists. The compounds of this invention have the following structure (I): 
including stereoisomers, prodrugs and pharmaceutically acceptable salts thereof,
wherein:
Q is a direct bond or xe2x80x94(CR8aR8b)rxe2x80x94Zxe2x80x94(CR10aR10b)sxe2x80x94;
A is O, S, or NR7;
r and s are the same or different and independently 0, 1, 2, 3, 4, 5 or 6;
n is 2, 3 or 4;
Z is a direct bond or xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NR9xe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94SO2xe2x80x94, xe2x80x94OSO2xe2x80x94, xe2x80x94SO2Oxe2x80x94, xe2x80x94SO2NR9xe2x80x94, xe2x80x94NR9SO2xe2x80x94, xe2x80x94COxe2x80x94, xe2x80x94COOxe2x80x94, xe2x80x94OCOxe2x80x94, xe2x80x94CONR9xe2x80x94, xe2x80x94NR9COxe2x80x94, xe2x80x94NR9CONR9a, xe2x80x94OCONR9xe2x80x94 or xe2x80x94NR9COOxe2x80x94;
R1 and R2 are the same or different and independently hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heterocycle, substituted heterocycle, heterocyclealkyl, substituted heterocyclealkyl, xe2x80x94C(R1a)(xe2x95x90NR1b) or xe2x80x94C(N R1aR1c)(xe2x95x90NR1b);
or R1 and R2 taken together with the nitrogen atom to which they are attached form a heterocycle ring or a substituted heterocycle ring;
R3a and R3b are the same or different and, at each occurrence, independently hydrogen, alkyl, substituted alkyl, alkoxy, alkylthio, alkylamino, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heterocycle, substituted heterocycle, heterocyclealkyl, substituted heterocyclealkyl, xe2x80x94COOR14 or xe2x80x94CONR14R15;
or R3a and R3b taken together with the carbon atom to which they are attached form a homocyclic ring, substituted homocyclic ring, heterocyclic ring or substituted heterocyclic ring;
or R3a and R3b taken together form xe2x95x90NR3c;
or R3a and the carbon to which it is attached taken together with R1 and the nitrogen to which it is attached form a heterocyclic ring or substituted heterocyclic ring;
R4 is higher alkyl, substituted alkyl, aryl, substituted aryl, heterocycle, substituted heterocycle, xe2x80x94COR11, xe2x80x94COOR11, xe2x80x94CONR12R13, xe2x80x94OR11, xe2x80x94OCOR11, xe2x80x94OSO2R11, xe2x80x94SR11, xe2x80x94SO2R11, xe2x80x94NR12R13, xe2x80x94NR11COR12, xe2x80x94NR11CONR12R13, xe2x80x94NR11SO2R12 or xe2x80x94NR11SO2NR12R13;
R5 is hydrogen, halogen, lower alkyl, substituted lower alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, alkoxy, alkylthio, alkylamino, cyano or nitro;
R6 is higher alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl;
R7 is hydrogen, xe2x80x94SO2R11, cyano, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl; and
R1a, R1b, R1c, R3c, R8a, R8b, R9, R9a, R10a, R10b, R11, R12, R13, R14 and R15 are the same or different and, at each occurrence, independently hydrogen, acyl, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heterocycle, substituted heterocycle, heterocyclealkyl or substituted heterocyclealkyl;
or R1a and R1b, R8a and R8b, R10a and R10b, R12 and R13, or R14 and R15 taken together with the atom or atoms to which they are attached form a homocyclic ring. substituted homocyclic ring, heterocyclic ring or substituted heterocyclic ring.
As used herein, the above terms have the following meaning:
xe2x80x9cAlkylxe2x80x9d means a straight chain or branched, noncyclic or cyclic, unsaturated or saturated aliphatic hydrocarbon containing from 1 to 10 carbon atoms, while the term xe2x80x9clower alkylxe2x80x9d has the same meaning as alkyl but contains from 1 to 6 carbon atoms. The term xe2x80x9chigher alkylxe2x80x9d has the same meaning as alkyl but contains from 2 to 10 carbon atoms. Representative saturated straight chain alkyls include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and the like; while saturated branched alkyls include isopropyl, sec-butyl, isobutyl, tert-butyl, isopentyl, and the like. Representative saturated cyclic alkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like; while unsaturated cyclic alkyls include cyclopentenyl and cyclohexenyl, and the like. Cyclic alkyls are also referred to herein as a xe2x80x9chomocyclesxe2x80x9d or xe2x80x9chomocyclic rings.xe2x80x9d Unsaturated alkyls contain at least one double or triple bond between adjacent carbon atoms (referred to as an xe2x80x9calkenylxe2x80x9d or xe2x80x9calkynylxe2x80x9d, respectively). Representative straight chain and branched alkenyls include ethylenyl, propylenyl, 1-butenyl, 2-butenyl, isobutylenyl, 1-pentenyl, 2-pentenyl, 3-methyl-1-butenyl, 2-methyl-2-butenyl, 2,3-dimethyl-2-butenyl, and the like; while representative straight chain and branched alkynyls include acetylenyl, propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl, 3-methyl-1-butynyl, and the like.
xe2x80x9cArylxe2x80x9d means an aromatic carbocyclic moiety such as phenyl or naphthyl.
xe2x80x9cArylalkylxe2x80x9d means an alkyl having at least one alkyl hydrogen atoms replaced with an aryl moiety, such as benzyl, xe2x80x94(CH2)2phenyl, xe2x80x94(CH2)3phenyl, xe2x80x94CH(phenyl)2, and the like.
xe2x80x9cHeteroarylxe2x80x9d means an aromatic heterocycle ring of 5- to 10 members and having at least one heteroatom selected from nitrogen, oxygen and sulfur, and containing at least 1 carbon atom, including both mono- and bicyclic ring systems. Representative heteroaryls are furyl, benzofuranyl, thiophenyl, benzothiophenyl, pyrrolyl, indolyl, isoindolyl, azaindolyl, pyridyl, quinolinyl, isoquinolinyl, oxazolyl, isooxazolyl, benzoxazolyl, pyrazolyl, imidazolyl, benzimidazolyl, thiazolyl, benzothiazolyl, isothiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, cinnolinyl, phthalazinyl, and quinazolinyl.
xe2x80x9cHeteroarylalkylxe2x80x9d means an alkyl having at least one alkyl hydrogen atom replaced with a heteroaryl moiety, such as xe2x80x94CH2pyridinyl, xe2x80x94CH2pyrimidinyl, and the like.
xe2x80x9cHeterocyclexe2x80x9d (also referred to herein as a xe2x80x9cheterocyclic ringxe2x80x9d) means a 4- to 7-membered monocyclic, or 7- to 10-membered bicyclic, heterocyclic ring which is either saturated, unsaturated, or aromatic, and which contains from 1 to 4 heteroatoms independently selected from nitrogen, oxygen and sulfur, and wherein the nitrogen and sulfur heteroatoms may be optionally oxidized, and the nitrogen heteroatom may be optionally quaternized, including bicyclic rings in which any of the above heterocycles are fused to a benzene ring. The heterocycle may be attached via any heteroatom or carbon atom. Heterocycles include heteroaryls as defined above. Thus, in addition to the heteroaryls listed above, heterocycles also include morpholinyl, pyrrolidinonyl, pyrrolidinyl, piperidinyl, hydantoinyl, valerolactamyl, oxiranyl, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl, tetrahydropyridinyl, tetrahydroprimidinyl, tetrahydrothiophenyl, tetrahydrothiopyranyl, tetrahydropyrimidinyl, tetrahydrothiophenyl, tetrahydrothiopyranyl, and the like.
xe2x80x9cHeterocyclealkylxe2x80x9d means an alkyl having at least one alkyl hydrogen atom replaced with a heterocycle, such as xe2x80x94CH2morpholinyl, and the like.
xe2x80x9cHomocyclexe2x80x9d (also referred to herein as xe2x80x9chomocyclic ringxe2x80x9d) means a saturated or unsaturated (but not aromatic) carbocyclic ring containing from 3-7 carbon atoms, such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclohexene, and the like.
The term xe2x80x9csubstitutedxe2x80x9d as used herein means any of the above groups (i.e., alkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, homocycle, heterocycle and/or heterocyclealkyl) wherein at least one hydrogen atom is replaced with a substituent. In the case of a keto substituent (xe2x80x9cxe2x80x94C(xe2x95x90O)xe2x80x94xe2x80x9d) two hydrogen atoms are replaced. When substituted one or more of the above groups are substituted, xe2x80x9csubstituentsxe2x80x9d within the context of this invention include halogen, hydroxy, cyano, nitro, amino, alkylamino, dialkylamino, alkyl, alkoxy, alkylthio, haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, heterocycle and heterocyclealkyl, as well as xe2x80x94NRaRb, xe2x80x94NRaC(xe2x95x90O)Rb, xe2x80x94NRaC(xe2x95x90O)NRaNRb, xe2x80x94NRaC(xe2x95x90O)ORbxe2x80x94NRaSO2Rb, xe2x80x94C(xe2x95x90O)Ra, xe2x80x94C(xe2x95x90O)ORa, xe2x80x94C(xe2x95x90O)NRaRb, xe2x80x94OC(xe2x95x90O)NRaRb, xe2x80x94ORa, xe2x80x94SRa, xe2x80x94SORa, xe2x80x94S(xe2x95x90O)2Ra, xe2x80x94OS(xe2x95x90O)2Ra and xe2x80x94S(xe2x95x90O)2ORa. In addition, the above substituents may be further substituted with one or more of the above substituents, such that the substituent substituted alky, substituted aryl, substituted arylalkyl, substituted heterocycle or substituted heterocyclealkyl. Ra and Rb in this context may be the same or different and independently hydrogen, alkyl, haloalkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heterocycle, substituted heterocycle, heterocyclealkyl or substituted heterocyclealkyl.
xe2x80x9cHalogenxe2x80x9d means fluoro, chloro, bromo and iodo.
xe2x80x9cHaloalkylxe2x80x9d means an alkyl having at least one hydrogen atom replaced with halogen, such as trifluoromethyl and the like.
xe2x80x9cAlkoxyxe2x80x9d means an alkyl moiety attached through an oxygen bridge (i.e. xe2x80x94O-alkyl) such as methoxy, ethoxy, and the like.
xe2x80x9cAlkylthioxe2x80x9d means an alkyl moiety attached through a sulfur bridge (i.e., xe2x80x94S-alkyl) such as methylthio, ethylthio, and the like.
xe2x80x9cAlkylsulfonylxe2x80x9d means an alkyl moiety attached through a sulfonyl bridge (i.e. xe2x80x94SO2-alkyl) such as methylsulfonyl, ethylsulfonyl, and the like.
xe2x80x9cAlkylaminoxe2x80x9d and xe2x80x9cdialkylaminoxe2x80x9d mean one or two alkyl moiety attached through a nitrogen bridge (i.e., xe2x80x94N-alkyl) such as methylamino, ethylamino, dimethylamino, diethylamino, and the like.
In one embodiment of this invention, A is O and representative GnRH receptor antagonists of this invention include compounds having the following structure (II): 
In another embodiment, Q is xe2x80x94(CR8aR8b)rxe2x80x94Zxe2x80x94(CR10aR10b)sxe2x80x94, r and s are both zero, and representative GnRH receptor antagonists of this invention include compounds having the following structure (III): 
In another embodiment, A is S, as represented by the following structure (IV): 
Similarly, in another embodiment, A is NR7, as represented by the following structure (V): 
In further embodiments of this invention, R6 is substituted or unsubstituted benzyl as represented by the following structure (VI) (wherein Y represents one or more optional substituents as defined above): 
In a more specific embodiment of structure (VI), A is O, n is 2, and each occurrence of R3a and R3b is H, as represented by the following structure (VII): 
With regard to the xe2x80x9cR1R2N(CR3aR3b)nxe2x80x94xe2x80x9d moiety of structure (I), n may be 2, 3 or 4. Accordingly, this moiety may be represented by the following structure (i) when n is 2, structure (ii) when n is 3, and structure (iii) when n is 3: 
wherein each occurrence of R3a and R3b above may be the same or different, and are as defined above. For example, when each occurrence of R3a and R3b in structures (i), (ii) and (iii) is hydrogen, the xe2x80x9cR1R2N(CR3aR3b)nxe2x80x94xe2x80x9d moiety has the structure R1R2N(CH2)2xe2x80x94, R1R2N(CH2)3xe2x80x94 and R1R2N(CH2)4xe2x80x94, respectively.
The compounds of the present invention may be prepared by known organic synthesis techniques, including the methods described in more detail in the Examples. However. in general, the compounds of structure (I) above may be made by the following Reaction Schemes. Specifically, compounds of structure (I) wherein A is oxygen may be made by Reaction Schemes A to E. Reaction Schemes F to K are appropriate for compounds of structure (I) wherein A is sulfur or NR7, as well as where A is oxygen. Reaction Scheme L shows conditions for the conversion of thiouracils (where A is sulfur) to embodiments wherein A is NR7. All substituents in the following Reaction Schemes are as defined above unless indicated otherwise. 
Allylurea (i) and substituted acetoacetate (ii) are condensed under acidic conditions in a solvent such as ethanol or DMF at 25 to 100xc2x0 C. and then cyclized under strongly basic conditions to give the substituted 3-allyl-2,4-pyrimidinedione (iii). Compound (iii) can then be modified by alkylation with an appropriate alkyl halide (where X is halogen) in a solvent such as DMF or ethanol for 1 hour to 2 days in the presence of a base such as sodium hydride or tetrabutylammonium fluoride to yield (iv). Oxidation of the allyl functionality, using osmium tetroxide and/or sodium periodate in solvent such as THF and/or water for 1-24 hours, gives aldehyde (v). Bromination of (v) using bromine or n-bromosuccinimide in a solvent such as acetic acid or chloroform for 1-24 hours resulted in brominated compound (vi). Reductive amination of (vi) with an appropriate amine using a reducing agent such as sodium triacetoxyborohydride in a solvent such as dichloroethane at 0 to 100xc2x0 C. for 1-24 hours gives (vii) which when coupled with an appropriate boronic acid in a solvent such as ethanol or toluene at 25 to 150xc2x0 C. for 1-24 hours in the presence of a Pd(0) catalyst gives (viii).
The final two steps of the above synthesis may also be reversed, the Suzuki coupling in that instance being the penultimate step and the reductive amination the final step. Alternatively, compound (iii) may be synthesized by the procedure in Example 2. 
Compound (iii) from Reaction Scheme Al may also be synthesized by condensing and cyclizing allyl isocyanate (viii) and appropriate aminoalkene ester (ix) such as ethyl 3-aminocrotonate in a solvent such as toluene or DMF at 25 to 100xc2x0 C. for 1-24 hours. 
Cyclization of (xi) and (xii) in a solvent such as ethanol or DMF at 25 to 150xc2x0 C. for 1 to 24 hours gives oxazime (xiii). Amination of (xiii) in a solvent such as DMF or ethanol at 25 to 150xc2x0 C. for 1-24 hours yielded uracil derivative (xiv). Alkylation of (xiv) by an appropriate alkyl bromide in the presence of a base such as sodium hydride or sodium hydroxide in a solvent such as THF or DMF at 0 to 100xc2x0 C. for 1-24 hours gives substituted uracil (xvi). The order of the reaction scheme may be changed allowing oxazine (xiii) to first be alkylated under conditions above to (xv) followed by amination to the product (xvi). 
Compound (xvii) or (xviii) react with an appropriately substituted isocyanate in a solvent such as toluene or chloroform at room temperature to 100xc2x0 C. for 1-24 hours as an alternative synthesis to intermediate oxazine (xv). Amination with a substituted amine in a solvent such as DMF or ethanol at a temperature of 25 to 100xc2x0 C. for a period of 1-24 hours results in product uracil (xvi). 
Intermediate (xvi) may be brominated using a brominating agent such as N-bromosuccinimide or bromine in a solvent such as acetic acid or chloroform at 0 to 100xc2x0 C. for a period of 1-24 hours to yield bromo compound (ixx). The bromo compound can undergo various palladium catalyzed cross coupling reactions. Compound (ixx) taken in solvent such as ethanol or THF under nitrogen atmosphere using an appropriate Pd(0) catalyst such as tetrakis(triphenylphosphine)Pd(0), may be reacted for 1-24 hours at 25 to 150xc2x0 C. with either an aryl boronic acid (ArB(OH)2 where Ar is substituted aryl or heteroaryl) to yield product (xx) or with a substituted vinyl boronic acid to give compound (xxi). Compound (ixx) taken in solvent such as ethanol or THF using an appropriate Pd(0) catalyst in the presence of carbon monoxide and boronic acid yields (xxiv) after 1-24 hours at 0 to 150xc2x0 C. Again using Pd(0) chemistry, compound (xxiii) is synthesized in a solvent such as THF or dioxane from the alkylation of (ixx) with an appropriate metal halide reagent for 1-24 hours at 0 to 150xc2x0 C. Compound (ixx) in the presence of a substituted acetylene, Pd(0) catalyst, metal halide such as CuI, and base such as triethylamine in an appropriate solvent such as acetonitrile or DMF at 25 to 150xc2x0 C. for 1-24 hours gives alkyne (xxii). Alkynyl uracil (xxii) may be selectively reduced to the alkene using a catalyst such as palladium/BaSO4 under hydrogen atmosphere in solvent such as ethyl acetate or methanol to give (xxi). 
Vinyl ester (xxvi) and (xxv) can be cyclized in a solvent such as DMF or EtOH at 25 to 150xc2x0 C. for 1-24 hours to give (xxvii). Alkylation of (xxvii) with an appropriate alkyl or aryl halide in a solvent such as DMF or THF in the presence of a base such as sodium hydride or sodium hydroxide for 1-24 hours at 0 to 150xc2x0 C. gives (xxviii). 
Vinyl ester (xxvi) can be condensed with a substituted amine in a solvent such as DMF or ethanol at 25 to 150xc2x0 C. for 1-24 hours to give (xxix). Cyclization of (xxix) with an isocyanate, isothiocyanate, or other appropriate compound in a solvent such as DMF, THF or dioxane, with or without a base such as sodium ethoxide or sodium hydride at 0 to 100xc2x0 C. for 1-24 hours gives product (xxviii). 
Compound (xxx) may be alkylated by an appropriate alkyl halide in the presence of a base such as sodium hydride or sodium hydroxide in a solvent such as THF or DMF at 0 to 50xc2x0 C. for 1-24 hours to give (xxxi), which under further alkylation by a second alkyl halide gives product (xxviii). 
Compound (xxxi) may be alkylated by an appropriate alkyl halide in the presence of a base such as sodium hydride or sodium hydroxide in a solvent such as THF or DMF at 0 to 100xc2x0 C. for 1-24 hours to give (xxxii). The terminal double bond is oxidized using an appropriate oxidizing reagent such as osmium tetroxide or sodium periodate in solvent such as THF and/or water for 1-24 hours at 0 to 100xc2x0 C. to give aldehyde (xxxiii). Reductive amination of (xxxiii) with an appropriate amine using a reducing agent such as sodium cyanoborohydride in a solvent such as dichloroethane or acetonitrile at 0 to 100xc2x0 C. for 1-24 hours gives (xxviii). 
Compound (xxxii) can be oxidized to the alcohol (xxxiv) first by hydroboration with a borane complex in a solvent such as THF followed by oxidation with ozone or hydrogen peroxide in a solvent such as methanol, ethanol and/or water at xe2x88x9225 to 100xc2x0 C. for a period of 0.5-24 hours. Treatment of (xxxiv) with mesyl or tosyl chloride in methylene chloride with a base such as triethylamine or pyridine at 0 to 100xc2x0 C. for 1-24 hours followed by reaction with an amine in a solvent such as DMF or toluene for 0.5-12 hours at 25 to 100xc2x0 C. gives (xxviii). 
Compound (xxxi) can be alkylated with an appropriate ester in a solvent such as DMF or ethanol in the presence of a base such as sodium hydride or sodium ethoxide at a temperature of 25 to 150xc2x0 C. for a period of 1-24 hours to give (xxxv). Ester (xxxv) in a solvent such as chloroform or benzene with substituted amine and Lewis acid such as triethylaluminum gives amide (xxxvi) after 1-24 hours at 0 to 100xc2x0 C. Reduction of (xxxvi) with lithium aluminum hydride or borane complex in a solvent such as THF or ether at 0 to 100xc2x0 C. for 1-12 hours gives product (xxviii). 
Thiouracil compound (xxxvii) in the presence of a substituted sulfonylisocyanate in a solvent such as benzene or toluene for 1-48 hours at 25 to 125xc2x0 C. gives sulfonamide (xxxviii). Thiouracil (xxxvii) chlorinated by thionyl chloride or phosphorous oxychloride at xe2x88x9225 to 100xc2x0 C. for 1-24 hours followed by amination with an appropriate amine in a solvent such as benzene or toluene at 25 to 150xc2x0 C. for 1-24 hours gives compound (xxxix). 
Substituted amine in the presence of urea or thiourea is heated at a temperature of 50-125xc2x0 C. for 0.5 to 12 hours to give (xl). Cyclization of (xl) with diketene at 50-150xc2x0 C. in acidic media such as acetic or formic acid for 5 minutes to 4 hours gives a mixture of isomers (xli) and (xlii). Halogenation of (xlii) using a halogenating reagent such as N-halosuccinimide in chloroform or bromine in acetic acid for 5 minutes to 24 hours gives halogenated product (xliii). 
Uracil compound (xliii) and an appropriately substituted alcohol are condensed under Mitsonobu conditions such as diethyl or dibutyl axodicarboxylate and triphenylphosphine in a solvent such as THF at 0-100xc2x0 C. for 0.5 to 10 hours to give compound (xliv). A Suzuki coupling of (xliv) and a boronic acid or boronic acid ester in a solvent such as ethanol or toluene at 25 to 150xc2x0 C. for 1-24 hours in the presence of a Pd(0) catalyst gives (xlv). Deprotection of the protected amine gives (xlvi). Reductive amination of (xlvi) with an appropriate aldehyde in a solvent such as methylene chloride or acetonitrile using a reducing agent such as sodium triacetoxyborohydride or sodium borohydride at 0 to 100xc2x0 C. for 1-24 hours gives (xlvii). 
Keto or aldehyde xlviii in the presence of chlorosulfonylisocyanate or chlorocarbonylisocyanate yields oxaz-2,4-dione xlix after stirring for 1-24 hours at 0xc2x0 C. to 75xc2x0 C. in a solvent such as THF or ether. Mitsonobu condensation with an appropriate alcohol gives l which when in the presence of amine R6NH2 at room temperature to 125xc2x0 C., with or without solvent such as DMF or catalyst such as acetic or hydrochloric acid, for xc2xd to 24 hours gives xlvii.
The compounds of the present invention may generally be utilized as the free acid or free base. Alternatively, the compounds of this invention may be used in the form of acid or base addition salts. Acid addition salts of the free amino compounds of the present invention may be prepared by methods well known in the art, and may be formed from organic and inorganic acids. Suitable organic acids include maleic, fumaric, benzoic, ascorbic, succinic, methanesulfonic, acetic, trifluoroacetic, oxalic, propionic, tartaric, salicylic, citric, gluconic, lactic, mandelic, cinnamic, aspartic, stearic, palmitic, glycolic, glutamic, and benzenesulfonic acids. Suitable inorganic acids include hydrochloric, hydrobromic, sulfuric, phosphoric, and nitric acids. Base addition salts included those salts that form with the carboxylate anion and include salts formed with organic and inorganic cations such as those chosen from the alkali and alkaline earth metals (for example, lithium, sodium, potassium, magnesium, barium and calcium), as well as the ammonium ion and substituted derivatives thereof (for example, dibenzylammonium, benzylammonium, 2-hydroxyethylammonium, and the like). Thus, the term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d of structure (I) is intended to encompass any and all acceptable salt forms.
In addition, prodrugs are also included within the context of this invention. Prodrugs are any covalently bonded carriers that release a compound of structure (I) in vivo when such prodrug is administered to a patient. Prodrugs are generally prepared by modifying functional groups in a way such that the modification is cleaved, either by routine manipulation or in vivo, yielding the parent compound. Prodrugs include, for example, compounds of this invention wherein hydroxy, amine or sulfhydryl groups are bonded to any group that, when administered to a patient, cleaves to form the hydroxy, amine or sulfhydryl groups. Thus, representative examples of prodrugs include (but are not limited to) acetate, formate and benzoate derivatives of alcohol and amine functional groups of the compounds of structure (I). Further, in the case of a carboxylic acid (xe2x80x94COOH), esters may be employed, such as methyl esters, ethyl esters, and the like.
With regard to stereoisomers, the compounds of structure (I) may have chiral centers and may occur as racemates, racemic mixtures and as individual enantiomers or diastereomers. All such isomeric forms are included within the present invention, including mixtures thereof. Compounds of structure (I) may also possess axial chirality which may result in atropisomers. Furthermore, some of the crystalline forms of the compounds of structure (I) may exist as polymorphs, which are included in the present invention. In addition, some of the compounds of structure (I) may also form solvates with water or other organic solvents. Such solvates are similarly included within the scope of this invention.
The effectiveness of a compound as a GnRH receptor antagonist may be determined by various assay methods. Suitable GnRH antagonists of this invention are capable of inhibiting the specific binding of GnRH to its receptor and antagonizing activities associated with GnRH. For example, inhibition of GnRH stimulated LH release in immature rats may be measured according to the method of Vilchez-Martinez (Endocrinology 96:1130-1134, 1975). Briefly, twenty-five day old male Spraque-Dawley rats are administered an GnRH antagonist in saline or other suitable formulation by oral gavage, sub-cutaneous injection, or intravenous injection. This is followed by sub-cutaneous injection of 200 ng GnRH in 0.2 ml saline. Thirty minutes after the last injection, the animals are decapitated and trunk blood collected. After centrifugation, the separated plasma is stored at xe2x88x9220xc2x0 C. until determination of the LH and FSH by radioimmunoassay. Other techniques for determining the activity of GnRH receptor antagonists are well known in the field, such as the use of cultured pituitary cells for measuring GnRH activity (Vale et al., Endocrinology 91:562-572, 1972), and a technique for measuring radioligand binding to rat pituitary membranes (Perrin et al., Mol. Pharmacol. 23:44-51, 1983).
For example, effectiveness of a compound as a GnRH receptor antagonist may be determined by one or more of the following assays.
Rat Anterior Pituitary Cell Culture Assay of GnRH Antagonists
Anterior pituitary glands are collected from 7-week-old female Sprague-Dawley rats and the harvested glands digested with collagenase in a dispersion flask for 1.5 hr at 37xc2x0 C. After collagenase digestion, the glands are further digested with neuraminidase for 9 min at 37xc2x0 C. The digested tissue is then washed with 0.1% BSA/McCoy""s 5A medium, and the washed cells suspended in 3% FBS/0.1 BSA/McCoy""s 5A medium and plated into 96-well tissue culture plates at a cell density of 40,000 cells per well in 200 xcexcl medium. The cells are then incubated at 37xc2x0 C. for 3 days. One pituitary gland normally yields one 96-well plate of cells, which can be used for assaying three compounds. For assay of an GnRH antagonist, the incubated cells are first washed with 0.1% BSA/McCoy""s 5A medium once, followed by addition of the test sample plus 1 nM GnRH in 200 xcexcl 0.1% BSA/McCoy""s 5A medium in triplicate wells. Each sample is assayed at 5-dose levels to generate a dose-response curve for determination of its potency on the inhibition of GnRH stimulated LH and/or FSH release. After 4-hr incubation at 37xc2x0 C., the medium is harvested and the level of LH and/or FSH secreted into the medium determined by RIA.
RIA of LH and FSH
For determination of the LH levels, each sample medium is assayed in duplicates and all dilutions are done with RIA buffer (0.01M sodium phosphate buffer/0.15M NaCl/1% BSA/0.01% NaN3, pH 7.5) and the assay kit is obtained from the Nation Hormone and Pituitary Program supported by NIDDK. To a 12xc3x9775 mm polyethylene test tube is added 100 xcexcl of sample medium diluted 1:5 or rLH standard in RIA buffer and 100 xcexcl of [125I]-labeled rLH (xcx9c30,000 cpm) plus 100 xcexcl of rabbit anti-rLH antibody diluted 1:187,500 and 100 xcexcl RIA buffer. The mixture is incubated at room temperature over-night. In the next day, 100 xcexcl of goat anti-rabbit IgG diluted 1:20 and 100 xcexcl of normal rabbit serum diluted 1:1000 are added and the mixture incubated for another 3 hr at room temperature. The incubated tubes are then centrifuged at 3,000 rpm for 30 min and the supernatant removed by suction. The remaining pellet in the tubes is counted in a gamma-counter. RIA of FSH is done in a similar fashion as the assay for LH with substitution of the LH antibody by the FSH antibody diluted 1:30,000 and the labeled rLH by the labeled rFSH.
Radio-iodination of GnRH Peptide
The GnRH analog is labeled by the chloramine-T method. To 10 xcexcg of peptide in 20 xcexcl of 0.5M sodium phosphate buffer, pH 7.6, is added 1 mCi of Na125I, followed by 22.5 xcexcg chloramine-T and the mixture vortexed for 20 sec. The reaction is stopped by the addition of 60 xcexcg sodium metabisulfite and the free iodine is removed by passing the iodinated mixture through a C-8 Sep-Pak cartridge (Millipore Corp., Milford, Mass.). The peptide is eluted with a small volume of 80% acetonitrile/water. The recovered labeled peptide is further purified by reverse phase HPLC on a Vydac C-18 analytical column (The Separations Group, Hesperia, Calif.) on a Beckman 334 gradient HPLC system using a gradient of acetonitrile in 0.1% TFA. The purified radioactive peptide is stored in 0.1% BSA/20% acetonitrile/0.1% TFA at xe2x88x9280xc2x0 C. and can be used for up to 4 weeks.
GnRH Receptor Membrane Binding Assay
Cells stably, or transiently, transfected with GnRH receptor expression vectors are harvested, resuspended in 5% sucrose and homogenized using a polytron homogenizer (2xc3x9715 sec). Nucleii are removed by centrifugation (3000xc3x97g for 5 min.), and the supernatant centrifuged (20,000xc3x97g for 30 min, 4xc2x0 C.) to collect the membrane fraction. The final membrane preparation is resuspended in binding buffer (10 mM Hepes (pH 7.5), 150 mM NaCl, and 0.1% BSA) and stored at xe2x88x9270xc2x0 C. Binding reactions are performed in a Millipore MultiScreen 96-well filtration plate assembly with polyethylenimine coated GF/C membranes. The reaction is initiated by adding membranes (40 ug protein in 130 ul binding buffer) to 50 ul of [125I]-labeled GnRH peptide (xcx9c100,000 cpm), and 20 ul of competitor at varying concentrations. The reaction is terminated after 90 minutes by application of vacuum and washing (2xc3x97) with phosphate buffered saline. Bound radioactivity is measured using 96-well scintillation counting (Packard Topcount) or by removing the filters from the plate and direct gamma counting. Ki values are calculated from competition binding data using non-linear least squares regression using the Prism software package (GraphPad Software).
Activity of GnRH receptor antagonists are typically calculated from the IC50 as the concentration of a compound necessary to displace 50% of the radiolabeled ligand from the GnRH receptor, and is reported as a xe2x80x9cKixe2x80x9d value calculated by the following equation:       K    i    =            IC      50              1      +              L        /                  K          D                    
where L=radioligand and KD=affinity of radioligand for receptor (Cheng and Prusoff, Biochem. Pharmacol. 22:3099, 1973). GnRH receptor antagonists of this invention have a Ki of 100 xcexcM or less. In a preferred embodiment of this invention, the GnRH receptor antagonists have a Ki of less than 10 xcexcM, and more preferably less than 1 xcexcM, and even more preferably less than 0.1 xcexcM (i.e., 100 nM). To this end, representative GnRH receptor antagonists of this invention which have a Ki of less than 100 nM when using the GnRH receptor membrane binding assay as described above include the following Compound Nos.
As mentioned above, the GnRH receptor antagonists of this invention have utility over a wide range of therapeutic applications, and may be used to treat a variety of sex-hormone related conditions in both men and women, as well as mammals in general. For example, such conditions include endometriosis, uterine fibroids, polycystic ovarian disease, hirsutism, precocious puberty, gonadal steroid-dependent neoplasia such as cancers of the prostate, breast and ovary, gonadotrophe pituitary adenomas, sleep apnea, irritable bowel syndrome, premenstrual syndrome, benign prostatic hypertrophy, contraception and infertility (e.g., assisted reproductive therapy such as in vitro fertilization).
The compounds of this invention are also useful as an adjunct to treatment of growth hormone deficiency and short stature, and for the treatment of systemic lupus erythematosis.
In addition, the compounds are useful in combination with androgens, estrogens, progesterones, and antiestrogens and antiprogestogens for the treatment of endometriosis, fibroids, and in contraception, as well as in combination with an angiotensin-converting enzyme inhibitor, an angiotensin II-receptor antagonist, or a renin inhibitor for the treatment of uterine fibroids. The compounds may also be used in combination with bisphosphonates and other agents for the treatment and/or prevention of disturbances of calcium, phosphate and bone metabolism, and in combination with estrogens, progesterones and/or androgens for the prevention or treatment of bone loss or hypogonadal symptoms such as hot flashes during therapy with a GnRH antagonist.
In another embodiment of the invention, pharmaceutical compositions containing one or more GnRH receptor antagonists are disclosed. For the purposes of administration, the compounds of the present invention may be formulated as pharmaceutical compositions. Pharmaceutical compositions of the present invention comprise a GnRH receptor antagonist of the present invention and a pharmaceutically acceptable carrier and/or diluent. The GnRH receptor antagonist is present in the composition in an amount which is effective to treat a particular disorderxe2x80x94that is, in an amount sufficient to achieve GnRH receptor antagonist activity, and preferably with acceptable toxicity to the patient. Typically, the pharmaceutical compositions of the present invention may include a GnRH receptor antagonist in an amount from 0.1 mg to 250 mg per dosage depending upon the route of administration, and more typically from 1 mg to 60 mg. Appropriate concentrations and dosages can be readily determined by one skilled in the art.
Pharmaceutically acceptable carrier and/or diluents are familiar to those skilled in the art. For compositions formulated as liquid solutions, acceptable carriers and/or diluents include saline and sterile water, and may optionally include antioxidants, buffers, bacteriostats and other common additives. The compositions can also be formulated as pills, capsules, granules, or tablets which contain, in addition to a GnRH receptor antagonist, diluents, dispersing and surface active agents, binders, and lubricants. One skilled in this art may further formulate the GnRH receptor antagonist in an appropriate manner, and in accordance with accepted practices, such as those disclosed in Remington""s Pharmaceutical Sciences, Gennaro, Ed., Mack Publishing Co., Easton, Pa. 1990.
In another embodiment, the present invention provides a method for treating sex-hormone related conditions as discussed above. Such methods include administering of a compound of the present invention to a warm-blooded animal in an amount sufficient to treat the an condition. In this context, xe2x80x9ctreatxe2x80x9d includes prophylactic administration. Such methods include systemic administration of a GnRH receptor antagonist of this invention, preferably in the form of a pharmaceutical composition as discussed above. As used herein, systemic administration includes oral and parenteral methods of administration. For oral administration, suitable pharmaceutical compositions of GnRH receptor antagonists include powders, granules, pills, tablets, and capsules as well as liquids, syrups, suspensions, and emulsions. These compositions may also include flavorants, preservatives, suspending, thickening and emulsifying agents, and other pharmaceutically acceptable additives. For parental administration, the compounds of the present invention can be prepared in aqueous injection solutions which may contain, in addition to the GnRH receptor antagonist, buffers, antioxidants, bacteriostats, and other additives commonly employed in such solutions.